[PATCH AUTOSEL 4.9 01/23] mac80211: Run TXQ teardown code before de-registering interfaces

[Sasha Levin]

From: Toke HÃiland-JÃrgensen <toke@xxxxxxx>

[ Upstream commit 77cfaf52eca5cac30ed029507e0cab065f888995 ]

The TXQ teardown code can reference the vif data structures that are
stored in the netdev private memory area if there are still packets on
the queue when it is being freed. Since the TXQ teardown code is run
after the netdevs are freed, this can lead to a use-after-free. Fix this
by moving the TXQ teardown code to earlier in ieee80211_unregister_hw().

Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Tested-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Toke HÃiland-JÃrgensen <toke@xxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 net/mac80211/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 2bb6899854d4..6389ce868668 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1164,6 +1164,7 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 #if IS_ENABLED(CONFIG_IPV6)
 	unregister_inet6addr_notifier(&local->ifa6_notifier);
 #endif
+	ieee80211_txq_teardown_flows(local);
 
 	rtnl_lock();
 
@@ -1191,7 +1192,6 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 	skb_queue_purge(&local->skb_queue);
 	skb_queue_purge(&local->skb_queue_unreliable);
 	skb_queue_purge(&local->skb_queue_tdls_chsw);
-	ieee80211_txq_teardown_flows(local);
 
 	destroy_workqueue(local->workqueue);
 	wiphy_unregister(local->hw.wiphy);
-- 
2.17.1